PLANT ORGANS AND ORGANISMS 
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layer. When the mesocarp is fleshy, as in the Peach, it is called the 
sarcocarp. 
When the endocarp within the sarcocarp is hard, forming a shell or 
stone, this is termed a putamen. 
Sutures. The ventral suture is a line formed by the coherent 
edges of a carpellary leaf. The dorsal suture is the mid-rib of the 
carpel. Parietal sutures are lines or furrows frequently visible on the 
walls of fruits, formed by the ripening of a compound ovary. They 
occur between its dorsal sutures and indicate the places of union 
between adjacent septa or of two parietal placentae. 
Valves. These are the parts into which the mature fruit separates 
to permit the escape of the seeds. Depending upon the number of 
these the fruit is said to be univalved , bivalved, trivalved, etc. 
Fig. 98.—Diagrams illustrating three forms of valvular dehiscence. A, Locu- 
licidal dehiscence showing each carpel split along its midrib or dorsal suture, 
the dissepiments remaining intact; B, septicidal dehiscence, in which splitting 
took place along the partitions; C, septifragal dehiscence, in which the valves 
broke away from the partitions. 
Dehiscence.—This is the opening of the pericarp to allow the 
seeds to escape. 
Fruits are either Dehiscent or Indehiscent according as they open to 
discharge their seeds spontaneously when ripe (dehiscent), or decay, 
thus freeing the seeds, or retain their seeds, the embryo piercing 
the pericarp in germination (- indehiscent ). Dehiscent fruits open reg¬ 
ularly, or normally, when the pericarp splits vertically through the 
whole or a part of its length, along sutures or lines of coalescence of 
contiguous carpels. Legumes usually dehisce by both sutures. 
Irregular or abnormal dehiscence has no reference to normal sutures, 
as where it is transverse or circumscissile, extending around the cap- 
